全文获取类型
收费全文 | 594篇 |
免费 | 12篇 |
国内免费 | 4篇 |
专业分类
测绘学 | 29篇 |
大气科学 | 46篇 |
地球物理 | 140篇 |
地质学 | 240篇 |
海洋学 | 50篇 |
天文学 | 81篇 |
自然地理 | 24篇 |
出版年
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 14篇 |
2013年 | 23篇 |
2012年 | 7篇 |
2011年 | 26篇 |
2010年 | 30篇 |
2009年 | 23篇 |
2008年 | 17篇 |
2007年 | 27篇 |
2006年 | 21篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 15篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1991年 | 17篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1983年 | 7篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1966年 | 6篇 |
1964年 | 6篇 |
1962年 | 4篇 |
1960年 | 6篇 |
1956年 | 4篇 |
1952年 | 5篇 |
1949年 | 4篇 |
1948年 | 5篇 |
排序方式: 共有610条查询结果,搜索用时 187 毫秒
81.
Time variable Earth’s gravity field from SLR satellites 总被引:4,自引:4,他引:0
82.
83.
84.
Winter-to-spring temperature dynamics in Turkey derived from tree rings since AD 1125 总被引:2,自引:1,他引:1
Ingo Heinrich Ramzi Touchan Isabel Dorado Liñán Heinz Vos Gerhard Helle 《Climate Dynamics》2013,41(7-8):1685-1701
In the eastern Mediterranean in general and in Turkey in particular, temperature reconstructions based on tree rings have not been achieved so far. Furthermore, centennial-long chronologies of stable isotopes are generally also missing. Recent studies have identified the tree species Juniperus excelsa as one of the most promising tree species in Turkey for developing long climate sensitive stable carbon isotope chronologies because this species is long-living and thus has the ability to capture low-frequency climate signals. We were able to develop a statistically robust, precisely dated and annually resolved chronology back to AD 1125. We proved that variability of δ13C in tree rings of J. excelsa is mainly dependent on winter-to-spring temperatures (January–May). Low-frequency trends, which were associated with the medieval warm period and the little ice age, were identified in the winter-to-spring temperature reconstruction, however, the twentieth century warming trend found elsewhere could not be identified in our proxy record, nor was it found in the corresponding meteorological data used for our study. Comparisons with other northern-hemispherical proxy data showed that similar low-frequency signals are present until the beginning of the twentieth century when the other proxies derived from further north indicate a significant warming while the winter-to-spring temperature proxy from SW-Turkey does not. Correlation analyses including our temperature reconstruction and seven well-known climate indices suggest that various atmospheric oscillation patterns are capable of influencing the temperature variations in SW-Turkey. 相似文献
85.
Marco Micheli Detlef Koschny Gerhard Drolshagen Olivier Hainaut Fabrizio Bernardi 《Earth, Moon, and Planets》2014,113(1-4):1-13
In this work we summarize the initial results of a targeted effort of the ESA NEO Coordination Centre to obtain additional observational data in order to eliminate or reduce the impact probability estimate of a subset of the known near-Earth objects representing the highest fraction of the total known impact risk, as measured by the Palermo Scale. 相似文献
86.
87.
Gerhard Schmidtke 《Solar physics》1981,74(1):251-263
The solar irradiance below 120 nm was first predicted by astronomers. Since its accurate measurement required the solution of a variety of technological problems, little is known about the variability before 1972, though for more than two decades data have been collected. Therefore, on a quantitative basis only a very rough picture can be given for the solar cycle 19. Also, not enough data with sufficient absolute accuracy are available to describe the solar EUV flux variations of the solar cycle 20, especially during the period of solar maximum. However, due to technological improvements of space and laboratory instrumentations, an almost complete set of data has been obtained from 1972 to date. These observations exhibit strong differences of the flux variations from solar cycle 20 to 21. - For the theoretical and for semi-empirical treatments of many aeronomic processes controlled by the solar EUV radiation, its adequate representation e.g. as indices is required. The problems involved and possible solutions are discussed. Results from some relevant aeronomically oriented computations based on variable solar EUV fluxes are presented.Proceedings of the 14th ESLAB Symposium on Physics of Solar Variations, 16–19 September 1980, Scheveningen, The Netherlands. 相似文献
88.
Gerhard Hafner 《Marine Policy》1981,5(3):281-282
While the Draft Convention still leaves the land-locked states with very considerable disadvantages, it can be said to represent a success for such states in so far as the notion of land-locked states forms a definite part of the proposed law of the sea and therefore provided them with the power to influence further developments. 相似文献
89.
90.
Gerhard Hensler Daniel Tschöke Dominik Bomans Alessandro Boselli 《Astrophysics and Space Science》2003,284(2):467-470
Observations of the Virgo Cluster galaxy NGC 4569 in soft X-rays and in Hα reveal both an asymmetrically distributed hot gaseous
halo and a giant filament of diffuse emission, respectively, extending from the same side of the disk, the latter one to at
least 8.8 kpc. A deep longslit spectrum along the filament shows velocities systematically different from the systemic velocity
of NGC 4569. With the inclination of the disk one can determine the Hα spur as a giant outflow in NGC 4569.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献